Sign holder



FIG. 1 is a front elevational view of a sign holder showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevational view thereof, with the left side elevational view being a mirror image thereof; and,

FIG. 6 is a perspective view thereof as it would be mounted on a support.

The portions shown in dashed lines in FIG. 6 show the environment of the sign holder and form no part of the claimed design. 

The ornamental design for a sign holder, as shown and described. 